1. Field of the Invention
The present invention relates to a method of cutting off glass panes or panels, especially rectangular glass panes or panels, from a continuously produced glass sheet, in which the glass sheet is continuously tested for glass faults prior to the cutting process, the glass sheet regions containing the glass faults or defects are determined and from the results of the fault detection an optimized cutting pattern for a given glass sheet section is determined by using a cutting optimizing device. The cutting pattern comprises a plan for cutting the glass panes or panels of respective predetermined sizes arranged next to each other in crosscut pieces out of the crosscut pieces.
The invention also relates to an apparatus for cutting off the glass panes from the glass sheet including a conveying device for the glass sheet and for the crosscut pieces cut from it, a fault detecting device for detecting faults in the glass sheet, a crosscutting device for cutting off crosscut pieces, a glass pane cutting device and a cutting optimization device connected to the fault detecting device, the crosscutting device and the glass pane cutting device. The cutting optimization device comprises means for calculating an optimized cutting pattern for a given glass sheet section.
2. Description of the Related Art
During glass pane manufacture, especially during manufacture of display glass, a glass sheet is continuously produced, so-called crosscut pieces are cut off in further process steps, glass borders of the crosscut pieces are removed and the glass panes are cut to the desired size from the crosscut pieces. The “crosscut pieces” by definition are glass sheet strips with borders extending perpendicular to the feed direction of the glass sheet, from which one or more useful glass panes are cut away.
Prior to cutting off the glass panes a fault detection process for detecting faults in the glass sheet is performed so that the regions, which are not acceptable because of either the number and/or type of faults or defects, can be located. During the determination of the cutting pattern, which provides a surface-covering glass pane arrangement, the fault information is considered so that as small-sized glass panes as possible contain the fault-containing glass sheet regions to be discarded, whereby the available glass sheet regions are cut out without gaps. The cutting pattern is designed so that the glass panes in the crosscut pieces are next to each other without gaps, so that the respective glass pane size defines the crosscut piece length. The crosscut pieces are placed next to each other without gaps. Since there are no strip-like waste regions between the crosscut pieces, which contain faults, they must be sorted out.
After the cutting process finished glass which contain the faults must be separated from the good glass panes.
When the batch permits the making of small-sized glass panes, the waste occurring in the known method can be decreased within certain limits. However in a batch from which only large-sized glass panes are made, these large panes thus must be sorted out, when only small regions have unacceptable faults within the glass panes.
Additional waste can arise when a border at the edge region is damaged during the cutting process. Also in this case the entire adjacent glass pane next to the border must be discarded.